Method of and apparatus for mining



Sept. 21,1937. -c. F. OSG OOD METHOD OF AND APPARATUS FOR MININGOriginal Filed NOV. 15 1935 7 Sheets-Sheet 1 I 1 liwzn m' 2395 17 @9003C. F. OSGOOD METHOD OF AND APPARATUS FOR MINING Sept. :21, 1937.

Original Filed Nov 15, 1955 7 Sheets-Sheet 2 Sept. 21, 1937. c.F. OSGOODMETHOD OF AND APPARATUS ,FOR MINING Original Filed Nov. 15, 1935 7Sheets-Sheet 5 III Sept. 21; 1937. c. F. oseooo ,09

r A METHOD OF AND APPARATUS FOR MINING Original Filed Nov. 15, 1935 7Sheets$heet 4 iewen ww g/zazifesfi 06510062 Sept. 21, 1937. c. F. ossooDMETHOD OF AND APPARATUS FOR MINING cQF. OSGOOD v 2,093,476 METHOD OF AIID APPARATUS FOR MINING I I Sept. 21, 1937. I

Original Filed Nov. 151955 I 147426225194 A aezzesiflsyoozi 7Sheets-Sheet 7 Patented Sept. 21, 1937 ,iAit

2,093,476 Msrnon or AND arram'rns FOR wnNrNe Charles F. Osgood,Claremont, N. H, assignor to Sullivan Machinery Company, a corporationof Massachusetts Application November 15, 1935, Serial No. 50,028

, Renewed November 30, 1936 Claims.

This invention relates to improved. methods of and apparatus for mining,and more particularly to an improved coal mining apparatus for cuttingthe coal in a coal seam and for blasting :the coal previously out,together with the improved methods ofuse-of such an apparatus.

It has previously been proposed to break down material from the solid byforming an opening in the material to be broken-using for that purpose adrilling implement--; confining within the opening soformed-specifically, within the drilling implement-a charge of a gas atblasting pressure; and suddenly releasing from its confinement, whilethe opening-forming implement remains in the opening, the charge intosaid opening. Thissubject matter is disclosed in paratus including, akerf cutter for cutting a plane kerf. It has also previously beenproposed to break down material by cutting an opening in the material bymeans of a suitable kerf-cutting implement-desirably after thepreliminary formation of and insuitable space relation to a kerf cut toprovide clearance towards which the material may be broken-and releasinginto the opening, while the kerf cutter remains therein, and through thekerf cutter, a fluid material breaking medium. This subject matter isdis closed in the Joseph F. Joy application, Serial No. 49,782, filedNov. 14, 1935, also assigned to my assignee; and this present inventionis also subordinate to the disclosure of that, application as to allcommon subject matter, both from its method and apparatus aspects; andessentially involves the feature of the confinement, prior to itsrelease, of a charge at blasting pressure within the opening and,specifically, within the kerf cutter, prior to its release into theopening.

An object of this invention is to provide improved methods of andapparatus for the mining of coal whereby the coal is cut and broken downfrom a coal seam in an improved manner. Another object is to provide animproved coal mining apparatus for cutting keris in a coal seam andthereafter releasing a coal breaking charge into the coal previously cutby the cutting means,

tobreak down the coal from the coal seam. A

further object is to provide an improved coal mining apparatus havingkerf cuttingmeans for cutting kerfs in thecoal seam and havingassociated with the kerf cutting means improved means for conducting a"blasting charge into the coal previously cut by the cutting means, todislodge the coal from the coal face. A still further object is toprovide an improved coal blasting means embodied in the kerf cutter ofthe kerf cutting means whereby, when the kerf cutter is inserted in thecoal, a powerful blasting charge at coal breaking pressure may bereleased from thekerf cutter into the coal to break down the latter. Yetanother object is to provide an improved kerf cutter having embodiedtherein means for confining a blasting charge at a relatively high coalbreaking pressure and ,for efiecting release of the "blasting chargeinto the .ccal to break down the coal by the action of the blastingpressure thereon and embodying discharge means for the blasting chargefor releasing the latter in planes perpendicular to the plane of thekerf cut by the kerf cutter,

thereby to attain apowerful breaking action div rectly on the coal to bebroken'down. A further object is to provide, in a coal breaking kerf,cutter of the above character,improved means embodied in the kerfcutter for confining a charge of pressure fluid at a relatively highblasting pressure and for suddenly releasing the charge from theconfining means. Still another object is to provide an improvedadjustable supporting structure for the coal cutting and blasting meanswhereby a blasting charge may be released into the coal at any desiredlocation in the coal face and in either rib, an element of the cuttingmeans of the apparatus constituting an element of the Yblasting means.Arfurther object is to provide an improved coal .blasting means embodiedin the kerf cutting means, wherein a highly compressed gas, such ashighly compressed air, is employed as a blasting medium. Other objectsand advantages of the in-' vention will, however, hereinafter more fullyappear.

In the accompanying drawings there are shown for purposes ofillustration one form and a modification thereof which the invention mayassume in practice. i

In these drawings,-

Fig. 1 is a plan View of a coal mining apparatus having embodied thereinone illustrative form of the improved coal blasting means.

Fig. 2 is a side elevational view of the mining apparatus shown inFig. 1. v Fig. 3 is an enlarged plan view of the rearward portion of theapparatus shown in Fig. 1, with the casing broken away to show detailsof the interior construction.

Fig. 4 is an enlarged view in longitudinal section taken substantiallyon line 3-4 of Fig. 3.

Fig. 5 is an enlarged plan view of the forward portion of the apparatusshown in Fig. 1.

Fig. 6 is a view in longitudinal section taken substantially on line 66of Fig. 5.

Fig. 7 is a diagrammatic view showing the hydraulic fluid system and theassociated control means.

Fig. 8 is an enlarged horizontal sectional View taken substantially online 83 of Fig. 4, illustrating the fluid compressor.

Fig. 9 is a detail sectional View showing the control valve for theblasting means.

Fig. 10 is an enlarged plan View, partially in horizontal section, ofthe kerf cutter, showing the blasting pressure confining and release.means embodied therein.

Fig. 11 is an enlarged sectional view taken in the plane of Fig. 10,showing details of construction of the blasting pressure confining andrelease means.

Fig. 12 is an enlarged cross sectional view taken substantially on linel2--l2 of Fig. 10, showing the blasting pressure confining chambers.

Fig. 13 is an enlarged fragmentary sectional view taken in the plane ofFig. 6, illustrating the improved tamping means associated with the kerfcutter.

Fig. 14 is an enlarged cross sectional view taken substantially on lineHil4 of Fig. 10, showing the blasting pressure release passages.

Figs. 15 and 16 are cross sectional views taken in the planes of Figs.12 and 14, respectively, illustrating a modified form of blasting means.

Fig. 17 is a diagrammatic plan view showing the apparatus in a mine withthe kerf cutter in a position to release a blasting charge into a coalseam, and illustrating the improved remote control means for theblasting charge release means.

Figs. 18 to 21, inclusive, are diagrammatic cross sectional viewsshowing various methods of cutting and blasting the coal in the coalseam.

Fig. 22 is a diagrammatic side view showing the mining apparatus in themine with the kerf cutter in a blasting position in the coal seam.

In this illustrative construction, both forms of the improved coalbreaking or blasting kerf cutter are shown embodied in a coal miningapparatus of the so-called universal cutter type, herein of the samegeneral character as that disclosed in a copending application to oneJoseph F. Joy, Ser. No. 20,826, filed May 10, 1935, although it will beevident that the improved coal blasting means may be embodied in thecutting means of mining apparatus of various other types.

:cation, the truck frame 2 has mounted thereon at its forward end ahorizontal turntable 5 journaled for rotation about a vertical axis withrespect to the truck frame on a forwardly projecting horizontal frameportion 6 extending in advance of the front truck wheels, the turntableaxisbeing located on the truck in advance of the front truck wheels.Pivotally mounted at 'l on the horizontal turntable 5 for verticalswinging movement with respect thereto is an elongated arm structure orboom '8 having mounted thereon at its forward extremity for rotationabout an axis extending longitudinally of the arm structure a revolvinghead 9 in turn. having pivotally mounted thereon to swing relativethereto about an axis [0 at right angles to the head axis a cuttersupport I l carrying a kerf cutter l2 of an improved design. The kerfcutter is in the form of an elongated plane cutter bar 13 having mountedfor circulation orbitally about its margin an endless cutter bitcarrying cutter chain M. Supported at the rearward portion of theswingable arm structure 8 is a motor l5 having its power shaft l6, asshown in Fig. 6, extending longitudinally of the arm structure andconnected through a coupling IT to a longitudinal shaft l8 suitablyjournaled within the arm structure, with its axis in coincidence withthe revolving head axis. Keyed to the forward end of the shaft I8 is abevel gear I!) which drives, through bevel gearing in a manner clearlydescribed in the above mentioned copending application, a bevel gear 20connected to a shaft 2 I. The shaft 2i is suitably journaled in thetiltable cutter support H and has keyed thereto a chain sprocket 22which engages and drives the endless cutter chain [4.

The cutter bar I3 is mounted on a. hanger 23 having an annular bearingportion 24 journaled on bearing sleeves supported by a cylindricalbearing support 25 formed integral with the tiltable cutter support H sothat the cutter bar may be swung relative to the support ll about theaxis of the shaft 2|. The hanger frame 23 is provided with a pluralityof apertures 26 within which a slidable locking pin 27 is adapted toproject to lock the bar hanger to the cutter support, the locking pinbeing guided on the cutter support and having suitable manual releasemeans 28. As shown most clearly in Fig. 12, the cutter bar has formedthereon longitudinal guides 29 mounted in longitudinal guideways 30formed on the hanger 23, and arranged between the hanger and the cutterbar is an adjusting screw 3| for adjusting the cutter bar longitudinallywith respect to the hanger to vary the tightness of the cutter chain M.

In accordance with this invention, supported within the truck frame is amotor driven pump 33 for supplying hydraulic pressure to hydrauliccylinders 34, 34 for rotating the turntable 5, hydraulic cylinders 35for vertically swinging the arm structure 8, hydraulic cylinders 36 forrevolving the head 9, a hydraulic cylinder 3'! for swinging the cuttersupport H, a hydraulic lock cylinder 38 for the revolving head 9 and thehydraulic operating cylinders for the truck drive control clutches andtruck wheel brake. Also mounted within the truck frame is motor drivenmeans for driving the truck wheels to propel the apparatus along themine trackway both during transport and the cutting operation. As thevarious hydraulic adjusting devices, the lock and clutch cylinders, thebrake operating cylinder and the truck wheel driving mechanism areclearly described in the copending application above referred to and donot per se enter into this invention, further detailed description ofthe specific structure thereof is herein considered unnecessary otherthan to state that the kerf cutter may be adjusted to cut horizontal andvertical kerfs at any desired location in the coal face and in eitherrim.

Now referring to the hydraulic system and associated control means shownin Fig. '7, it will be noted that the pump 33 is driven by a motor 39(see Figs. 3 and 4) which also drives the transmission mechanism forpropelling the apparatus ina manner clearly described in the abovementioned Joy application, Ser. No. 20,826. This pump 33 is arranged ina tank 40 adapted to contain a liquid, preferably oil, and the pump,submerged in the liquid, is adapted to supply hydraulic pressure to thevarious hydraulically operated devices of the apparatus. Arranged withinthe truck frame is a horizontal valve box M of a design similar to thatdescribed in the above mentioned copending application, and this valvebox has formed therein a series of horizontal valve bores eachcontaining a balanced-type slide valve for controlling the flow ofhydraulic pressure to the various hydraulic cylinders. The pump 33 isherein of the variable displacement, triple rotor type of a conventionaldesign and is provided with the usual variable displacement controlvalves for regulating the pressure in the fluid system. The dischargeside of the pump 33 is connected through a conduit 42 to the supplypassage of the valve box 4|, while the discharge passages of the valvebox are connected through branched conduits 43, 43 to a conduit 44leading to the tank. Conduits connect the hydraulic cylinders 34, 35,36, 31, and 38 and the truck drive control clutch and truck wheel brakecylinders, with the valve box 4!, and as previously mentioned, thisvalve box contains slide valves for controlling the flow of hydraulicpressure through these conduits to the cylinders. As these variousconduits and the particular slide valve structure are likewise clearlydescribed in the above mentioned Joy application, further descriptionthereof is herein considered unnecessary other than to state that theturntable may be rotated, the arm structure 8 swung vertically, therevolving head 9 rotated and the cutter support ll tilted, to vary theposition of the kerf cutter and for swinging the kerf cutter during thecutting operation.

Now referring to the improved blasting means embodied in the keri cutterfor confining therein a charge of pressure fluid at a blasting pressure,and the particular cutter bar structure associated therewith, it will benoted that the cutter bar 53 (see Figs. 12 and 14) comp-rises paralleltop and bottom plates '35 and 47 secured as by rivets 58 to lateralbar-like projections 49 formed integral with a centrally located,longitudinally extending cylinder block 55 herein extending lengthwiseof the cutter bar throughout a substantial portion of its length.Interposed between and secured tothe top and bottom plates by rivets 52at the tip end of the cutter bar is an end block 52 of generallysemi-circular shape, and the plates 55 and 4? cooperate with the blocks55 and 52 to form a guideway 53 about the margin of the cutter bar,within which the endless cutter chain it is guided. In thisconstruction, the hanger guides 29 on the cutter bar are preferablyformed integral with the cylinder block 5|]. As clearly shown in Figs.10, 11, and 12, the cylinder block 55 is formed with parallel bores 54,54 extending longitudinally of the cutter bar, and these bores, ashereinafter described, constitute chambers for receiving and confiningcharges of pressure fluid at a blasting pressure. In this instance, theend block 52 of the cutter bar forms a discharge cap having axialorifices 55 communicating with alined openings 56 in the cylinder blockand connected by oppositely extending discharge passages 51, 57 with theexteriorof the cutter bar, these discharge passages preferably chargesfrom the charge receiving chambers in planes perpendicular to the planeof the cutter bar. Alined with the chamber-forming bores 54,

the bores 58 and engaging the control cylinders 59 are plugs 52 forsealing the bores against leakage, there being interposed between theplugs and the control cylinders suitable sealing gaskets 63. Formed ineach of these control cylinders is a control chamber 64 containing areciprocable control piston 65. The piston rods 55 of the controlpistons 65 extend inwardly within the pressure chambers 55, 54 and havefixed to their inner extremities pressure release valves 51, 6'! adaptedto seat at 58 at the inner ends of the pressure chambers to preventcommunication of the discharge orifices 55 with the pressure cham bers55, the valve seats being formed on the inner end walls of the boresproviding the openings v 55. Positioned between shoulders at the rearend of the chamber bores 54 and the adjacent end surfaces of the controlcylinders 59 are heavy steel plates or discs H to which are secured hatleathers I2, surrounding and adapted to seal on the exterior surfaces ofthe valve rods 55 which pass therethrough. The control pistons 65 eachconsist of a steel plunger l3 carrying a cup leather 74 held in positionby a keeper l5 threaded on the valve rod. Suitable check valves. F6 areprovided in the plungers 13 as a means for permitting the flow of highpressure air from the control chambers 65 at the outer sides of thecontrol pistons through axial passages ii in the valve rods andcommunicating radial passages '58, into the pressure receiving chambers55, and preventing flow in the reverse direction. Passages E5 in thecontrol cylinders connect grooves 85 surrounding the control cylinderswith the control chambers, and

these grooves communicate with a transverse passage 8! formed in thecylinder block. A longitudinal pressure fluid supply passage 82 in thecylinder block communicates with the transverse passage 8|. Theintroduction of high pressure air through the passages 82, Si, grooves85 and passages 19 to the control chambers at the outer sides of thecontrol pistons results in axial movement of the valve and pistonassemblies to bring the valves 51 into tight sealing engagement withtheir seats 68 at the ends of the chamber bores.

the control chambers past the check valves i5 and through the passages Hand i8 into the pressure chambers 54. As the pressure builds up in thechambers 54, high pressure air will pass from the chambers 54 along thevalve rods 65 into the spaces at the inner sides of the control pistonsand between said control pistons and the metal plates 1 I the hatleathers 12 functioning as check valves opening toward such spaces. Inother words, air under pressure from the chambers 54 passes between thehat leathers l2 and the valve rods and into the spaces between the innersides of the control passages and the discs H. It will be observed,however, that rapid reverse flow along the outside of the valve rodscannot occur when the pressure in the chambers 54 falls because of thecheck valve action of the hat leathers 72 which then takes place. Whencharges of high pressure air of desired value have been in- At the sametime the high pressure air flows from troduced into the pressurechambers 55, clischarge thereof is effected by cutting oil the supplynecting the latter to atmosphere. Any suitable means, such as athree-way valve as shown in Fig. 9, or a more complex mechanism, may beused for this purpose. This then results immediately in the lowering ofthe pressure in the control chambers 64 at the outer sides of thecontrol pistons, and bearing in mind that the pressure of the airtrapped in the spaces at the inner sides of the control pistons betweenthe latter and the discs l! is substantially the same as that of thecharges of pressure that were introduced into the pressure chambers 54,it will be apparent that the reduction of pressure in chambers M- at theouter sides of the control pistons immediately results in axial movementof the valve and piston assemblies toward the left from the positionshown in Fig. 10 and in opening of the valves 07. Note, of course, thatthe effective area of the valves fill within the chambers 54 is lessthan the efiective area of the right hand sides of the pistons 65. Theinitial opening of the pressure release valves 6'] naturally results inan immediate and extremely rapid drop in pressure within the chambers54, but in view of the check valve action of the hat leathers 12, thepressure trapped between the discs H and the inner sides of the controlpistons will be sufficiently maintained to preclude the pressure in thecontrol chambers outside the control pistons from reclosing the valves8?. Thus the compressed air in the spaces at the inner sides of thecontrol pistons serves to move the valve and piston assembliespositively toward open position and to maintain them in that positionuntil the charges of blasting pressure have been released from thechambers 54 It will thus be seen that any desired blasting pressure maybe built up within the chambers 50, it being possible for the operatorto determine, by means of a usual gage in the compressed air supply lineor the compressor discharge pipe, the pressure of the blasting chargesin accordance with the requirements of the coal to be broken.

The fluid compressing means associated with the blasting pressurereceiving and confining means in the kerf cutter, comprises an aircornpressor 05 of an extremely compact design, supported within therearward portion of the truck frame at the rear of the driving motor 39for the fluid pump and truck wheel driving mechanism, in a positionsubstantially to counterbalance the kerf cutting mechanism. This aircompressor is of the horizontal four-stage high pressure type comprisinga low pressure cylinder 86, a secondstage cylinder S'l, a third-stagecylinder 89 and I a high pressure cylinder 89, these cylinderscontaining reciprocable pistons 90, 9|, 92, and 93, respectively,connected by connecting rods to a crank shaft 9 3. The compressorcylinders are provided with usual intake and discharge valves, and areconnected through piping to intercooling means generally designated 95,through which the compressed air flows between the difierent stages ofcompression, and the high pressure cylind-er 89 is provided with adischarge pipe 96 through which the highly compressed air is finallydischarged from the compressor. The compressor discharge pressure isextremely high; it sometimes reaching a pressure exceeding ten thousandpounds per square inch. As this comv pressor is of a well knowncommercial design, further description of the detailed structure thereofis herein considered unnecessary. The compressor is driven by the motor39 through a spur gear 9! keyed to the rear end of the motor fices 55and discharge passages 51.

power shaft and meshing with a spur gear 98 connectible by a multi-discclutch 99 of a usual design to a shaft I00. The shaft I is alined withthe compressor crank shaft 94 and-is connected to the latter through afly wheel coupling IOI. In this illustrative construction, the dischargepipe 96 of the compressor is connected through a flexible tubing I02 toa coupling I03 threaded within the valve box I04 of the threeway valveabove referred to, and is communicable under the control of a manuallyoperable valve element I05 through a coupling I06 to a flexible tubingI01, the latter leading to a connection I08 (see Fig. 6) on the armstructure 8. Leading from the connection I08 and extending along the armstructure is a flexible tubing I09, this tubing passing out of the armstructure through an opening H0 and connected at its outer extremity toa coupling III. The coupling iII is connected through a pipe II2 to thesupply passage 82 in the cylinder block of the cutter bar. As shown inFig. 6, the pipe II2 extends through a longitudinal slot I I3 in the barhanger 23 so that the cutter bar may be adjusted along its guidewayswith respect to the hanger in the manner above described. When the valveelement I05 is in the position shown in Fig. 9, highly compressed airmay flow from the compressor through the air discharge pipe 9'5, tubingI02, the passage in the valve I05, the tubing I01, and tubing I09 to thepassage 82 in the cutter bar and thence, in the manner previouslydescribed, to the chambers 54 of the blasting charge receiving andconfining means. When the valve element I05, shown in Fig. 9, is turnedinto its opposite position, the tubing IiJI is connected to exhaustthrough a vent passage IM, and as a result the control chambers 64 ofthe blasting means are vented, thereby to effect, in the manner abovedescribed, sudden opening of the blasting pressure release valves El torelease the blasting charges from the chambers 50, through the ori- Thevalve box I04 shown in Fig. 9 may be mounted on the rear end of thetruck frame, or if desired may be located at a point remote from thecoal face, the flexible supply tubing I02, I01 being of sufficientlength to enable location of the control valve I05 at a remote point.There is sufiicient flexibility in the tubing I09 extending along thearm structure to enable rotation of the head 9 and tilting of thesupport II so that irrespective of the position of the kerf cutter,compressed air may be supplied to the blasting means embodied in thekerf cutter.

In the modified form of construction shown in Figs. and 16, the cylinderblock 50 of the cutter bar is formed with but a single centrally locatedbore II5 similar to the parallel bores above described and havingsimilarly arranged therein a valve mechanism for confining the blastingcharge in the chamber and for effecting release of the blasting charge.Formed in the end block 52 at the tip end of the bar is an axialdischarge orifice II6 communicable with the chamber 5 and connectedthrough downwardly inclined discharge passages II! with the exterior ofthe cutter bar at the bottom surface of the cutter bar. It isaccordingly evident that when the blasting pressure has been built up inthe chamber H5 and the valve mechanism is operated to eifect release ofthe charge, the blasting pressure flows from the chamber I I5 throughthe axial discharge orifice I I6 and the discharge passages II'I to acton the coal at one side of the cutter bar. Otherwise this form of theinvention is the same as that above described.

In both forms of the invention self-tamping means is provided, herein inthe form of a U-shaped cuttings-retaining member I20 secured tothecutter bar hanger 23 and extending about the rearward portion of thecutter chain of the cutter bar. As shown most clearly in Fig. 13, thecutter bar is provided with an inclined wedging surface IZI, whilesecured to the opposite surface of the cutter bar is a wedge block I22having an inclined wedging surface H23. This cuttings-retaining memberI20 and the inclined wedging surfaces Hi, I23 cause the rear end of theopening formed by the kerf cutter, as the latter is fed in an endwisedirection into the coal seam, to clog with cuttings when the inclinedsurfaces and the retaining member are brought up against the coal face,thereby to tamp the outer end of the opening formed by the kerf cutterso that when the blasting charges are released from the kerf cutter, thetamping T, clogging the outer end of the opening, impedes the fiow ofthe blasting pressure outwardly through the opening so that asubstantial blasting effect is transmitted directly to the coal to bebroken.

The general mode of operation of the improved coal cutting and blastingapparatus is as follows: The apparatus may be propelled along the minetrackway at either a relatively high transport speed or a relatively lowspeed suitable for cutting, in the manner clearly described in the abovementioned copending application, and when the working place is reachedwith the apparatus in the position shown diagrammatically in Figs. 17

and 22, the turntable 5, arm structure 8, revolving head 9 and cuttersupport ll may be adjusted to move the kerf cutter l2 into any desiredlocation with respect to the working face and either rib. When the kerfcutter is suitably positioned, it may be sumped in, swung arcuately inits plane and withdrawn from the coal, in the manner well understood bythose skilled in the art, to form a plane kerf in the coal seam. InFigs. 18 and 22 a horizontal plane kerf at the level of the mine flooris indicated at A. When the cut in the coal is completed, the armstructure and cutter support may be swung to position the kerf cutternear the roof level, and

thereafter the kerf cutter may be sumped in an endwise direction intothe coal in the position indicated at B in Fig. 18. When the kerf cutteris in the position indicated at B highly compressed air is supplied fromthe air compressor to the blasting charge confining means in the kerfcutter, and thereafter blasting charges of highly compressed air aresuddenly released fromthe kerf cutter to break down the coal above thekerf A. As previously mentioned, the control valve element I05 foreffecting release of the blasting charges from the kerf cutter may belocated at the rear end of the truck frame, and suitable shielding meansmay be set up toprotect the operator during the blasting operation. Itis desirable, however, to locate the control valve element 105 at apoint remote from the coal face during the blasting operation, asillustrated in Fig. 17. To complete the breaking down of the coal abovethe horizontal kerf A, the kerf cutter may thereafter be inserted in anendwise direction into the coal successively into the positionsindicated at C and D in Fig. 18 and blasting charges released into thecoal, when the kerf cutter is so'positioned, to break down completelythe undercut coal from the coal face. In

Fig. 19, a vertical kerf E is cut in the coal face midway between theribs in planes perpendicular to the horizontal kerf A. The kerf cutteris then sumped in an endwise direction into the coal to the positionindicated at F in Fig. 19 and blasting charges released into the coal tobreak down the coal between the right hand rib and the vertical kerf E.Thereafter, the kerf cutter is positioned at G in Fig. 19 and blastingcharges are released in the coal between the left hand rib and thevertical kerf E to complete the breaking down of the face. In Fig. 20parallel vertical kerfs H and I are cut at the ribs perpendicular to thehorizontal kerf A and the kerf cutter is inserted successively inpositions J and K and blasting charges released into the coal to breakdown the coal between the vertical kerfs. In Fig. 21, parallel verticalkerfs L and Mare cut in the coal face in spaced relation between theribs in planes perpendicular to the horizontal kerf A and the kerfcutter is thereafter moved successively to the positions N, O and P andblasting charges released into the coal to break down the coal betweenthe ribs and between the vertical kerfs.

As a result of this invention, it will be noted that an improvedcoal'mining apparatus of the combined cutting and blasting type isprovided whereby the coal in the coal seam may be quickly andexpeditiously cut and broken down, thereby reducing the time consumed inthe preparation of the coal for the loading machine. It will also benoted that by embodying the improved blasting means in the kerf cutterof a coal cutting apparatus of the type disclosed, it is possible torelease a blasting charge into the coal at any desired location in thecoal face and in either rib. It will further be evident that bycombining the blasting means with the kerf cutting means of a coalcutting machine in the manner disclosed, it is possible to cut the coaland thereafter insertthe kerf cutter into the coal to form a blastopening, and, without removing the kerf cutter from the opening, torelease blasting charges in the opening to break down the coal, therebygreatly reducing the time consumed in the mining cycle. It will also beevident that by the provision of air compressing means which operates tosupply compressed air to the air receiving means in the kerf cutterduring the cutting operation, the cutting and blasting functions may beeffected in a relatively rapid succession. Further, by combining thecutting and blasting means in a self-contained unitary apparatus, notonly is the time consumed in the cutting and blasting. of the coalsubstantially reduced, but the expense necessitated by separate piecesof heavy equipment performing distinct functions, is also greatlyreduced. It will also be noted that by incorporating the improvedblasting type kerf cutter in a coal mining apparatus of the typedisclosed, the hydraulically operated adjusting and supporting means forthe kerf cutter act as a recoil means for absorbing any shocks whichmight occur when the blasting charges are released from the kerf cutterinto the coal seam, thereby reducing the possibility of injury to theadjusting and supporting structure. Other uses and advantages of theimproved coal mining and blasting apparatus will be clearly apparent tothose skilled in the art.

While there are in this application specifically described one form anda modification thereof which the invention may assume in practice, itwill be understood that this form and modification are shown forpurposes of illustration and that the invention may be modified andembodied in various other forms without departing from its spirit or thescope of the appended claims.

What I claim as new and desire to secure by Letters Patent is:

1. In an apparatus of the character described, a kerf cutter for cuttinga plane kerf in a coal seam, means embodied in said kerf cutter forconfining a blasting charge at coal breaking pressure, discharge meansfor said confining means, and means for controlling said discharge meansfor effecting sudden release of the blasting charge from said confiningmeans into the coal seam to break down the coal previously cut by saidkerf cutter.

2. In an apparatus of the character described, a kerf cutter for cuttinga. plane kerf in a coal seam, means embodied in said kerf cutterproviding a chamber for confining a blasting charge at coal breakingpressure, and means for eiiecting sudden release of the blasting chargefrom said chamber into the coal seam previously cut by said kerf cutterto break down the coal.

3. In combination, a kerf cutter for cutting a plane kerf in a minewall, means embodied in said kerf cutter for confining a charge ofpressure fluid at a blasting pressure, and means for eiiecting suddenrelease of the charge from'said confining means to eilect blasting.

4. In combination, a kerf cutter for cutting a plane kerf in a minewall, means embodied in, said kerf cutter for confining a charge ofpressure fluid at a blasting pressure, and means operable from a remotepoint for efiecting rapid release of the charge from said confiningmeans to efiect blasting.

5. In combination, a kerf cutter for cutting a plane kerf in a minewall, means embodied in said kerf cutter providing a chamber forconfining a charge of pressure fluid at a blasting pressure, dischargemeans for said chamber, and a valve in said chamber for rapidlyreleasing the charge from said chamber through said discharge means toeiTect blasting.

6. In combination, a kerf cutter for cutting a plane kerf iri a minewall, means embodied in said kerf cutter providing a pair of parallelchambers for receiving separate charges of pressure fluid at a blastingpressure, discharge means for said chambers, and valve means in saidchambers respectively for rapidly releasing the blasting charges fromsaid chambers through said discharge means to effect blasting.

7. In combination, a kerf cutter for cutting a plane kerf in a minewall, means embodied in said kerf cutter providing a pair of parallelchambers for receiving separate charges of pressure fiuid at blastingpressure, discharge means for said chambers, and valve means in saidchambers for confining the charges in said chambers and operable at willfor effecting sudden simultaneous release of said charges from saidchambers through said discharge means to effect blasting.

8. In combination, an elongated plane cutter bar having an endlesscutter chain guided for circulation about its margin, means embodied insaid cutter bar for confining a blasting charge at a coal breakingpressure, discharge means for said confining means, and means foreifecting sudden release of the blasting charge from said confiningmeans through said discharge means to efiect blasting.

9. In combination, an elongated plane cutter bar having an endlesscutter chain guided for circulation about its margin, means embodied insaid cutter bar providing a chamber for receiving a blasting charge at acoal breaking pressure, a valve in said chamber for confining the chargetherein and for suddenly releasing the charge to efiect blasting, andcontrol means for said valve.

10. In combination, an elongated plane kerf cutter, means embodied insaid kerf cutter for confining a blasting charge at coal breakingpressure, and means for suddenly releasing the charge from saidconfining means in a direction perpendicular to the plane of the kerfcutter.

11. In combination, an elongated plane kerf cutter, means embodied insaid kerf cutter for receiving a charge of pressure fluid at a blastingpressure, and means for effecting sudden release of the blasting chargefrom said receiving means in a direction perpendicular tothe plane ofthe kerf cutter.

12. In combination, a kerf cutter for cutting a plane kerf in a minewall, means embodied in said kerf cutter for receiving a charge ofpressure fluid at blasting pressure, and a differential valve mechanismin said receiving means for confining the charge in said receiving meansand for suddenly releasing the charge from said receiving means toeffect blasting.

13. In combination, a kerf cutter for cutting a plane kerf in a minewall, means embodied in said kerf cutter for receiving a charge ofpressure fiuid at blasting pressure, and a difierential valve mechanismin said receiving means for confining the charge in said receiving meansand for suddenly rel-easing the charge from said receiving means toefiect blasting, and means for controlling said valve mechanism from apoint remote from said kerf cutter.

14. In a coal cutting and blasting apparatus, a portable base, a kerfcutter mounted on said base and adapted to cut a plane kerf in a mineWall, a fiuid compressor mounted on said base, means embodied in saidkerf cutter providing a chamber for receiving a charge of pressure fluidat a blasting pressure, means for conducting compressed fiuid from saidcompressor to said charge receiving chamber irrespective of the adjustedposition of said kerf cutter, and means under operator control foreffecting rapid release of the blasting charge from said chamber when apredetermined blasting pressure is attained therein.

15. In a coal cutting and breaking apparatus, a. portable base, a kerfcutter mounted on said base and adapted to cut a plane kerf in a minewall, a fluid compressor mounted on said base, means embodied in saidkerf cutter providing a chamber for receiving a charge of compressedfluid at a blasting pressure, means for conducting compressed fiuid fromsaid compressor to said charge receiving chamber, valve means forconfining the charge in said chamber and for releasing the charge toeffect blasting, and means operable from a point remote from said kerfcutter for efiecting opening of said valve means rapidly to release thecharge from said chamber.

16. The method of dislodging material from a mine Wall which comprisescutting the material with a suitable elongated kerf-cutting implement toprovide an opening substantially rectangular in cross section on a planeperpendicular to its depth and to the length of said kerf-cuttingimplement and having two of its mutually opposite bounding surfacessubstantially plane and parallel to each other and spaced from eachother by a distance less than half their width, said Opening having oneof said two surfaces facing generally in the direction in which it isdesired to exert a material dislodging force, whereby a blastingpressure released into said opening will exert its rupturing force ingreater degree in the desired direction rather than in a direction atright angles to such direction, confining a blasting charge within theopening so formed in the material, and while the cutting implementremains in said opening releasing the blasting charge from itsconfinement into said opening.

17. The method of dislodging material from a mine wall which comprisescutting the material with a suitable elongated kerf-cutting implement toprovide in the material an opening having a pair of mutually oppositebounding surfaces extending longitudinally of said opening, and furtherhaving another pair of mutually opposite bounding surfaces alsoextending longitudinally thereof, said last mentioned surfaces eachextending between and connecting said first mentioned surfaces, andbeing plane and each of at least twice the width of said first mentionedmutually opposite surfaces, said opening having one of said pair ofplane parallel surfaces facing generally in the direction in which thematerial dislodging force is to be exerted, whereby a blasting pressurereleased into said opening will exert its major force in the desireddirection, confining a blasting charge within the opening so formed inthe material, and, while the cutting implement remains in the material,releasing, through the cutting implement, the blasting charge from itsconfinement Within the opening in the material formed by the cuttingimplement, into said openmg.

18. A method of cutting and blasting coal comprising the steps ofinserting a kerf-cutting implement into the coal to form a plane kerftherein, sumping the kerf-cutting implement in an endwise direction intothe coal to form an open ing at a point spaced from said plane kerf,confining a blasting charge at coal breaking pressure within the openingformed by said cutting implement, and finally, While the kerf-cuttingimplement remains in said opening, releasing the blasting charge at coalbreaking pressure from its confinement within said opening into thelatter, to break down the coal previously out by the cutting implement.

19. A method of cutting and blasting coal comprising the steps ofinserting a kerf-cutting implement into the coal to form a plane kerf,sumping the kerf-cutting implement in an endwise direction into the coalto form an opening at a point spaced from said plane kerf, confiningwithin said kerf-cutting implement a blasting charge at coal breakingpressure, and finally, while the kerf-cutting implement remains in saidopening, releasing into said opening, in a direction perpendicular tothe plane of said kerf, said blasting charge at coal breaking pressure,to break down the coal previously cut by the cutting implement.

20. A method of cutting and blasting coal comprising the steps ofinserting a kerf-cutting implement into the coal to form a plane kerftherein, sumping the kerf-cutting implement in an endwise direction intothe coal to form an opening at a point spaced from said plane kerf,confining a blasting charge at coal breaking pressure within the openingformed by said cutting implement, and finally, while the kerf-cuttingimplement remains in said opening, releasing from within the cuttingimplement the blasting charge at coal breaking pressure from itsconfinement in said opening, into the latter, to break down the coalpreviously out by the cutting implement.

CHARLES F. OSGOOD.

